Flexible lightweight Bi₂O₃ -rubber based materials for X-ray protection

The flexible X-ray protective materials are commonly made of lead rubber. They have heavy weight, high biological toxicity, poor flexibility and aging resistance. The "weak absorption zone" in the energy range of 40-88 keV threaten environmental safety and human health. Bi2O3-rubber based flexible X-ray protective materials were prepared by rubber production process. The micromorphology, shore hardness, specific gravity, mechanical properties and radiation protective properties were characterized and analyzed. The results showed that Bi2O3 particles dispersed in natural rubber (R) matrix uniformly. The shore hardness of samples fluctuated between 41 degrees and 46 degrees with the increasing Bi2O3 content, lower than the Level 1 index requirement of the hardness (<= 80 degrees) of lead-free composite protective materials. The specific gravity increased from 1.35 g/cm(3) to 2.38 g/cm(3), which reduced approximately 34% comparing with the commercial protective materials containing Pb. The breaking strength and breaking elongation meet the index requirements in National standard GB 16757-2016. When Bi2O3 content reached 300 parts, the highest lead equivalent and maximum shielding ratio were 0.3012 mmPb and 52.95% respectively. It meets the index requirement of lead equivalent of 0.25 mmPb <= Pb <= 0.35 mmPb for the front sheet of protective clothing. The effective shielding range of the protective material R/Bi2O3(100/300) was mainly in the range of incident energy of 65 similar to 100 keV and 164-250 keV, which covered the "weak absorption zone" of lead.